Process for incorporating compounds of barium in oil



United States Patent 0 PROCESS FOR INCORPORATING COMPOUNDS 1 0F BARIUM IN OIL Kenneth L. Kreuz and Morris A. Wiley, Fishkili, N.Y.,

and Richard C. Givens, Port Arthur, Tex., assignors to Texaco Inc., a corporation of Delaware No Drawing. Filed Mar. 13, 1957, Ser. No. 645,673

4 Claims. (Cl. 252-18) This invention pertains to a method of incorporating basic compounds of barium such as oxides, hydroxides, and basic salts in oils, particularly oils of lubricating grade; and also concerns novel oil compositions containing such compounds.

During normal operation of internal combustion engines, acids are formed in the lubricating oil itself and in the combustion chamber. The acids formed in the lubricating oil itself are normally caused by oxidation of the lubricating oil during engine operation. The result ing organic acids and peroxides break down the lubricating oil and contribute to wear by corrosion. The combustion chamber acids normally come from the combustion products of the fuel. For example, when high sulfur fuels are used in diesel engines, sulfuric acid is formed from the sulfur. This sulfuric acid finds its way into the crankcase along with the blow-by gases. Detergents are frequently incorporated in lubricating oil compositions for use as dispersing agents and as neutralizing agents for these acids.

The process of the present invention incorporates substantial amounts of a high quality detergent metal additive in an oil at a relatively low cost per unit of added metal. These desirable results are achieved by first introducing into a body of such oil (advantageously in either powder form or as an oil slurry) a basic compound of barium, preferably selected from the group consisting of oxides, hydroxides, and basic salts such as carbonates. Then oxidation is accomplished by blowing gaseous oxygen (generally in air) through the resulting mixture while heating it at a temperature of at least 400 P. which is above the decomposition temperature of the metal carboxylate salts which would be formed and retained at lower blowing temperatures. Such salts are well known to aggravate bearing corrosion. Their presence is minimized by the present invention.

The quantity of metal incorporated into an oil by the process described above generally is much more than would be required in the final lubricating oil itself. Therefore, the oil obtained as a product of the process may be considered as a concentrate when it contains more than 1% by weight of barium, l-l7% being usual, and is generally diluted with additional mineral oil to reduce the metal to between 0.25 and 5% by weight (half or more being carbonate), before being used for lubricating an engine.

Lubricating oils in which barium oxides and hydroxides can be dispersed according to the present invention include a wide variety of mineral hydrocarbon oils such as naphthenic base, paraflin base, and mixed base oils. Also, synthetic hydrocarbon oils can be used, such as a butylene polymer. Examples of typical mineral oils of lubricating grade which have been treated by our process are the following three prepared by distillation from a paraflin base crude oil followed by furfural refining, light acid 3,085,064 Patented Apr. 9, 1963 treating, clay contacting, and solvent dewaxing. The oil designations here used will be carried into the examples.

In carrying out the process described above the temperature of the oil should generally be 400 F. or above while blowing the oil with oxygen, and it is generally desirable not to exceed a top limit of 700 F. to avoid excessive decomposition of the oil. Within this broad operable temperature range, it has been found that we cellent results are obtained by maintaining the temperature between 400 and 450 F. The higher the temperature the more rapid is the reaction, and the greater is the amount of barium incorporated in the oil. For example, at a temperature of 350 F. twelve hours of air blowing were required to incorporate about 2.5% of barium in mineral oil A, and at 400 F. for 6 hours; whereas at 450 F. only one hour was required for the same result. On the other hand, 4 hours of blowing at 450 F. introduced more than 6% of barium; whereas 6 hours of blowing at 350 and 300 gave less than 2% in each instance.

It should also be noted that the amount of barium incorporated by our process increases with the time of oxidation as well as with the temperature. For example, at 450 F. 4% of barium was incorporated in oil A in two hours, whereas more than 6% of barium was incorporated in four hours. In general, the blowing time should exceed 2 hours for acceptable results.

Generally our novel process is carried out by blowing air through the mineral oil so that the oxygen content elfects the necessary reaction even though diluted with atmospheric nitrogen. However, it is to be understood that oxygen can be passed through as substantially pure oxygen or ozone; or either form in mixture with other gases, and in the same or other proportions than in air. The rate of reaction naturally should increase with increasing oxygen purity. The term oxygen as used in the claims is intended to embrace any of the foregoing conditions.

When the barium oxides and hydroxides have been dispersed in mineral oil by our novel process and excess solids have been filtered out, the resulting oil concentrate composition is clear, filterable, and stable. The metal is then present largely as a dispersion of its carbonate in the oil, rather than solely as carboxylate salts which result predominantly both from the addition of the metal hydroxide to an oil subsequent to air blowing, and from air blowing at too low a temperature.

Other supplemental additives may be used in the final lubricating oil compositions made from our concentrate. The lubricating oil compositions may contain oxidation inhibitors, such as organo esters of phosphorus (e.g., zinc cetylphenyl dithiophosphate and calcium cetylphenyl dithiophosphate); metal salts of thiocarbamic acids (e.g., zinc dibutyl dithiocarbamate); sulfides (e.g., sulfurized olefins, or P S -p1'nene reaction products, etc.); amines (phenyl alpha naphthyl amine; 1,4-diamino (dodecyl) u anthraquinone; p,p'-dioctyl diphenyl amine; N-diethyl thiocarbamyl-p phenylene diamine, etc.).

Furthermore, the final lubricating oil compositions may contain pour point depressants, corrosion inhibitors, oiliness agents, extreme pressure agents, blooming agents, compounds for enhancing the viscosity index of hydrocarbon oils; grease-forming agents; other dispersants and detergents, etc.

The following examples illustrate the effectiveness of our process for introducing metal compounds into mineral oils:

EXAMPLE I 1,285 grams of anhydrous barium hydroxide were mixed with kilograms of oil C and, while stirring, air was then blown through the mixture at a rate of liters per minute (l./min.) for six hours while the temperature of the oil was maintained at 350 F. The mixture was then heated rapidly over minutes to 450 F. while air blowing was continued. After cooling and filtering the resulting concentrate product was found to contain 3.2% of barium and 0.29% CO and had a Neut. No. (alkaline) of 4.4.

CFR Engine Test 23.7 parts by weight of this product were then blended with 76.3 parts of oil A and the resulting lubricant containing 0.76% of barium was tested in the CFR (Cooperative Fuels Research) engine low temperature ring wear test in comparison with base oil A. This test measures the amount of protection afforded by an oil against corrosion wear caused by low temperature operating conditions. The CFR engine test was performed in a CFR single cylinder 3 /4 x 4 /2 internal combustion engine having a cast iron piston and babbitt metal bearings, operating at 900 r.p.m. The oil pressure was about 20 p.s.i. and the oil temperature in the sump was about 120 F. The temperature of the cooling water was 80 F. at discharge. It was found that the weight loss of the top compression ring after 20 hours was reduced by 59% compared to the base oil.

Supercharged Caterpillar Engine Test ST-1 The same concentrate was also blended with a viscosity index residual distillate base oil and other additives to provide a lubricating oil containing 16.7% by weight of concentrate (which provides 0.54% of barium), 2.0% by weight of normal calcium petroleum sulfonate concentrate, and 1.2% by weight of a neutral terpene- P 8 reaction product. This lubricating oil was then tested for engine cleanliness for 50 hours in the supercharged caterpillar engine test ST-l (super charge pressure 45 in. Hg absolute) in a single cylinder caterpillar diesel engine having an aluminum alloy piston with 3 compression and 1 oil rings operating at 900 r.p.m. at a load of about 33 brake horsepower, a jacket temperature of 155195 F. and an oil temperature in the sump of 200 F. and an oil pressure of 30 p.s.i.

When burning a fuel containing 0.6% of sulfur in the engine, the lubricating oil atlorded a piston demerit rating of only 28, based on the piston cleanliness, compared to for the piston with the base oil alone, 70 for the piston with the base oil plus 2% by weight of the same normal calcium petroleum sulfonate concentrate, and 53 for the piston with the base oil containing both 2% of the same normal calcium petroleum sulfonate concentrate and 1.2% of the same neutral terpene-P S reaction product concentrate.

EXAMPLE H 918 grams of barium oxide and 108 ml. of water (to hydrate the barium oxide) were mixed with 3000 grams of oil B and then blown with air flowing at 10 l./min. for six hours at 350 F. while stirring. A sample of the product was then taken, filtered, and found to contain only 1.26% of barium. The rest of the product was then heated to 450 F. during one hour while continuing the air blowing, after which the product was found to contain 4.90% of barium after filtering.

EXAMPLE III 307 grams of barium oxide were mixed with 1000 grams of oil C and blown for four hours at 350 F. with air flowing at 10 l./min. while stirring. The product was then heated rapidly to 400 F, blown for 30 minutes at this temperature, and then found to contain 3.32% of barium after filtering.

EXAMPLE IV 458 grams of barium oxide were mixed with 2700 grams of butylene polymer and 54 ml. water and, while stirring, air was blown through the mixture at a rate OZ l0 l./rnin. while heating to 350 P. Then 300 grams of basic barium petroleum sulfonate (11% Ila) was added and the oxidation was continued three hours at 350 F. The temperature was then gradually raised over one hour to 450 F. and oxidation continued for one hour at 450 F. The filtered product contained 16.6% Ba by weight.

Physical tests characterizing the polybutylene polymer charged above include:

Flash, Cleveland open cup, F. 240 Viscousity, SSU at F. 270 Viscosity, SSU at 210 F. 40.6 Molecular wt. 324

EXAMPLE V 307 grams barium oxide were mixed with 1000 grams of a naphthene base lubricating oil (having a viscosity of 46.5 SSU at 210 F. and 311 SSU at 100 F), and 36 ml. water. The reaction mixture was heated to 350 F., while stirring and blowing with air at the rate of 10 l./min. and oxidation was continued for six hours at 350 F. The temperature was then rapidly raised to 400 F. and oxidation continued for 15 min. at 400 F. The filtered product analyzed 3.7% Ba by weight.

EXAMPLE VI 2700 grams of oil B, 300 grams of basic barium petroleum sulfonate, 918 grams of barium oxide, and 108 ml. of water were mixed together and blown with air at a rate of 10 l./min. for 4 hours while maintaining the temperature at 450 F. Samples taken at 1, 2, and 4 hours had barium contents of 2.85%, 3.72%, and 6.34%, respectively.

Under otherwise identical conditions, but using a temperature of 400 the barium contents after 6 hours was about 2.5%. Using temperatures of 350 and 300, less than 2% of barium was introduced in each instance.

The mechanism of our reaction is not completely understood, but present evidence suggests that the overall reaction may be summarized as consisting of (l) oxidation and formation of sparingly soluble barium soaps, and (2) decarboxylation of the metal soaps to yield an oil dispersable form of barium carbonate or base. Below about 400 F., step (2) does not proceed readily and the oil is left with an undesirably high ratio of metal soaps to dispersed metal base; whereas at or above 400 F. step (2) proceeds quite readily, as desired.

This application contains subject matter in common with application Serial No. 645,666, now Patent No. 3,006,847 filed concurrently herewith by Wiley and Kreuz entitled Incorporation of Alkali and Alkaline Earth Metals in Oil, and Resulting Product; and with application Serial No. 645,667, now abandoned, filed concurrently herewith by Kluge, Wiley and Kreuz entitled Oil Containing Alkali and Alkaline Earth Metal Basic Compound, and Process for Producing Same.

Obviously many modifications and variations of the invention, as hercinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore,

only such limitations should be imposed as are indicated in the appended claims,

We claim:

1. A process for preparing a detergent concentrate which comprises providing a mixture consisting essentially of a hydrocarbon lubricating oil, selected from the class consisting of mineral lubricating oils and alkylene polymer oils, and a barium compound selected from the class consisting of barium oxide and barium hydroxide in an amount sufficient to provide about 8-22 percent by weight of barium in the said mixture, heating the said mixture at a temperature in about the range 400-700 F. but below the decomposition temperature of the said lubricating oil for about 1-6 hours While blowing air through the said mixture at a rate of about 0.09-06 liter of air per hour per gram of the said lubricating oil, and separating any unreacted barium compound from the resulting product.

2. The process according to claim 1 wherein the said mixture is heated at a mixrnum temperature of about 450* F.

6 3. The process according to claim 1 wherein the said hydrocarbon lubricating oil is a refined paralfiru'c oil having a viscosity SUS at 210 F. in the range 43.3-65.4, inclusive.

4. The process according to claim 1 wherein the said hydrocarbon lubricating oil is a naphthenic oil.

References Cited in the file of this patent UNITED STATES PATENTS 2,008,490 Dietrich July 16, 1935 2,055,043 Nelson Sept. 22, 1936 2,079,051 Sullivan et a1 May 4, 1937 2,274,057 Gerlicher Feb. 24, 1942 2,417,428 McLennan Mar. 18, 1947 2,430,864 Farkas et al Nov. 18, 1947 2,447,794 Brewer Aug. 24, 1948 2,779,737 Koft Jan. 29, 1957 2,895,978 Brooks July 21, 1959 2,955,084 Bartleson et al. Oct. 4, 1960 2,982,728 Whitney May 2, 1961 

1. A PROCESS FOR PREPARING A DETERGENT CONCENTRATE WHICH COMPRISES PROVIDING A MIXTURE CONSISTING ESSENTIALLY OF A HYDROCARBON LUBRICATING OIL, SELECTED FROM THE CLASS CONSISTING OF MINERAL LUBRICATING OILS AND ALKYLENE POLYMER OILS, AND A BARIUM COMPOUND SELECTED FROM THE CLASS CONSISTING OF BARIUM OXIDE AND BARIUM HYDROXIDE IN AN AMOUNT SUFFICIENT TO PROVIDE ABOUT 8-22 PERCENT BY WEIGHT OF BARIUM IN THE SAID MIXTURE, HEATING THE SAID MIXTURE AT A TEMPERATURE IN ABOUT THE RANGE 400-700*F. BUT BELOW THE DECOMPOSITION TEMPERATURE OF THE SAID LUBRICATING OIL FOR ABOUT 1-6 HOURS WHILE BLOWING AIR THROUGH THE SAID MIXTURE AT A RATE OF ABOUT 0.09-0.6 LITER OF AIR PER HOUR PER GRAM OF THE SAID LUBRICATING OIL, AND SEPARATING ANY UNREACTED BARIUM COMPOUND FROM THE RESULTING PRODUCT. 